/***
 * Copyright 2002-2010 jamod development team
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * Original implementation by jamod development team.
 * This file modified by Charles Hache <chache@brood.ca>
 ***/

package net.wimpi.modbus.msg;

import net.wimpi.modbus.procimg.InputRegister;
import net.wimpi.modbus.procimg.ProcessImageFactory;
import net.wimpi.modbus.ModbusCoupler;
import net.wimpi.modbus.Modbus;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

/**
 * Class implementing a <tt>ReadInputRegistersRequest</tt>. The implementation
 * directly correlates with the class 0 function <i>read multiple registers (FC
 * 4)</i>. It encapsulates the corresponding response message.
 * 
 * @author Dieter Wimberger
 * @version @version@ (@date@)
 */
public final class ReadInputRegistersResponse extends ModbusResponse {

	// instance attributes
	private int m_ByteCount;
	// private int[] m_RegisterValues;
	private InputRegister[] m_Registers;

	/**
	 * Constructs a new <tt>ReadInputRegistersResponse</tt> instance.
	 */
	public ReadInputRegistersResponse() {
		super();
		setFunctionCode(Modbus.READ_INPUT_REGISTERS);
	}// constructor

	/**
	 * Constructs a new <tt>ReadInputRegistersResponse</tt> instance.
	 * 
	 * @param registers
	 *            the InputRegister[] holding response input registers.
	 */
	public ReadInputRegistersResponse(InputRegister[] registers) {
		super();
		setFunctionCode(Modbus.READ_INPUT_REGISTERS);
		m_ByteCount = registers.length * 2;
		m_Registers = registers;
		// set correct data length excluding unit id and fc
		setDataLength(m_ByteCount + 1);
	}// constructor

	/**
	 * Returns the number of bytes that have been read.
	 * <p/>
	 * 
	 * @return the number of bytes that have been read as <tt>int</tt>.
	 */
	public int getByteCount() {
		return m_ByteCount;
	}// getByteCount

	/**
	 * Returns the number of words that have been read. The returned value
	 * should be twice as much as the byte count of the response.
	 * <p/>
	 * 
	 * @return the number of words that have been read as <tt>int</tt>.
	 */
	public int getWordCount() {
		return m_ByteCount / 2;
	}// getWordCount

	/**
	 * Sets the number of bytes that have been returned.
	 * <p/>
	 * 
	 * @param count
	 *            the number of bytes as <tt>int</tt>.
	 */
	private void setByteCount(int count) {
		m_ByteCount = count;
	}// setByteCount

	/**
	 * Returns the <tt>InputRegister</tt> at the given position (relative to the
	 * reference used in the request).
	 * <p/>
	 * 
	 * @param index
	 *            the relative index of the <tt>InputRegister</tt>.
	 * @return the register as <tt>InputRegister</tt>.
	 * @throws IndexOutOfBoundsException
	 *             if the index is out of bounds.
	 */
	public InputRegister getRegister(int index)
			throws IndexOutOfBoundsException {

		if (index >= getWordCount()) {
			throw new IndexOutOfBoundsException();
		} else {
			return m_Registers[index];
		}
	}// getRegister

	/**
	 * Returns the value of the register at the given position (relative to the
	 * reference used in the request) interpreted as usigned short.
	 * <p/>
	 * 
	 * @param index
	 *            the relative index of the register for which the value should
	 *            be retrieved.
	 * @return the value as <tt>int</tt>.
	 * @throws IndexOutOfBoundsException
	 *             if the index is out of bounds.
	 */
	public int getRegisterValue(int index) throws IndexOutOfBoundsException {

		if (index >= getWordCount()) {
			throw new IndexOutOfBoundsException();
		} else {
			return m_Registers[index].toUnsignedShort();
		}
	}// getRegisterValue

	/**
	 * Returns a reference to the array of input registers read.
	 * 
	 * @return a <tt>InputRegister[]</tt> instance.
	 */
	public InputRegister[] getRegisters() {
		return m_Registers;
	}// getRegisters

	public void writeData(DataOutput dout) throws IOException {
		dout.writeByte(m_ByteCount);
		for (int k = 0; k < getWordCount(); k++) {
			dout.write(m_Registers[k].toBytes());
		}
	}// writeData

	public void readData(DataInput din) throws IOException {
		setByteCount(din.readUnsignedByte());

		InputRegister[] registers = new InputRegister[getWordCount()];
		ProcessImageFactory pimf = ModbusCoupler.getReference()
				.getProcessImageFactory();
		for (int k = 0; k < getWordCount(); k++) {
			registers[k] = pimf.createInputRegister(din.readByte(),
					din.readByte());
		}
		m_Registers = registers;
		// update data length
		setDataLength(getByteCount() + 1);
	}// readData

	public String toString() {
		return "ReadInputRegisterResponse - Words: " + getWordCount();
	}

}// class ReadInputRegistersResponse
